We often abort a recovery after sending a status request to a remote node.
We want to ignore any potential status reply we get from the remote node.
If we get one of these unwanted replies, we've often moved on to the next
recovery message and incremented the message sequence counter, so the
reply will be ignored due to the seq number. In some cases, we've not
moved on to the next message so the seq number of the reply we want to
ignore is still correct, causing the reply to be accepted. The next
recovery message will then mistake this old reply as a new one.
To fix this, we add the flag RCOM_WAIT to indicate when we can accept a
new reply. We clear this flag if we abort recovery while waiting for a
reply. Before the flag is set again (to allow new replies) we know that
any old replies will be rejected due to their sequence number. We also
initialize the recovery-message sequence number to a random value when a
lockspace is first created. This makes it clear when messages are being
rejected from an old instance of a lockspace that has since been
recreated.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The down-conversion optimization was resulting in the lkb flags being
cleared because the stub message reply had no flags value set. Copy the
current flags into the stub message so they'll be copied back into the lkb
as part of processing the fake reply. Also add an assertion to catch this
error more directly if it exists elsewhere.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
When recoveries are aborted by other recoveries we can get replies to
status or names requests that we've given up on. This can cause problems
if we're making another request and receive an old reply. Add a sequence
number to status/names requests and reject replies that don't match. A
field already exists for the seq number that's used in other message
types.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
To aid debugging, it's useful to be able to see what nodeid the dlm is
waiting on for a message reply.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Display more information from debugfs, particularly locks waiting for
a master lookup or operations waiting for a remote reply.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This changes the way the dlm handles user locks. The core dlm is now
aware of user locks so they can be dealt with more efficiently. There is
no more dlm_device module which previously managed its own duplicate copy
of every user lock.
Signed-off-by: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
In dlm_grant_after_purge() we were holding a hash table read_lock while
calling put_rsb() which potentially removes the rsb from the hash table,
taking the same lock in write. Fix this by flagging rsb's ahead of time
that have been purged. Then iteratively read_lock the hash table, find a
flagged rsb, unlock, process rsb.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch removes support for range locking from the DLM
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.
It implements VAX-style locking modes.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>
